Impact of exposure to extreme heat events during pregnancy on the incidence of congenital heart disease in offspring: a meta-analysis
Bibliographic record
Abstract
Background The aetiology of congenital heart disease (CHD) is multifactorial. Environmental risk factors have emerged as an important modifiable determinant of several congenital cardiac conditions. Previous studies have shown a strong relationship between CHD and air pollution. Much less is known about the influence of ambient temperature on CHD. The primary objective of this meta-analysis was to examine the association between exposure to extreme heat events (EHE) during pregnancy and CHD in the offspring. Methods comprehensive literature search was conducted using electronic databases such as Scopus and PubMed, along with a review of secondary references. This process yielded eight studies that met the inclusion criteria: four from the USA, two from China, one from Israel and one from Canada. The risk of bias was assessed using the Newcastle Ottawa scale. Mixed-effect regression was used to pool the estimates of individual studies. Heterogeneity was measured by I2. Results were visualised by a forest plot, a Baujat plot and an albatross plot. Subgroup analyses were performed for climate zones, exposure definitions and the study region. As a sensitivity analysis, a leave-one-out meta-analysis was performed to assess the robustness of the estimates. Results Exposure to EHE during pregnancy increased the risk for CHD in the offspring (OR=1.12, 95% CI 1.04 to 1.34). Studies from the USA observed the smallest effect (OR=1.01, 95% CI 0.91 to 1.13), studies in the continental climate zone observed a slightly larger effect (OR=1.07, 95% CI 0.97 to 1.19), and studies from the temperate climate zone observed the largest effect (OR=1.35, 95% CI 1.23 to 1.48). Subgroup analysis was conducted with respect to exposure, effect definition and region. The residual heterogeneity measures were 88% (exposure), 61% (effect definition) and 38% (Region). Conclusion The association between prenatal EHE exposure and future risk of CHD has important implications for pregnant mothers, infant health and health policy. Future studies should explore the additional burden of CHD contributed by current trends in global ambient temperature in other parts of the world. PROSPERO registration number CRD42023455934
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.012 | 0.023 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.016 | 0.072 |
| Bibliometrics | 0.005 | 0.005 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".